Infoporn: When Is the Next Major Hurricane Going to Hit?

Every year, the Atlantic hurricane season starts on June 1, kicking off its own storm of hyped-up coverage from meteorologists looking out for the next big one. If you’ve grown sick of the weatherman crying wolf, there’s good reason: In the past nine years, the eastern seaboard hasn’t seen a single major hurricane, defined as a Category 3 storm or higher, make landfall. The East coast has seen its fair share of hurricanes since the massively destructive seasons in 2005 and 2006—Sandy in 2012, Irene in 2011, and Ike in 2008—but none quite hit the bar.

This is weird. A study published last week in Geophysical Research Letters looked at just how rare a hurricane drought like this is, analyzing weather records back to 1851. Turns out it’s the longest stretch without a major hurricane ever. The last time the US came close to it was all the way back in the 1860s, when the coast went 8 years dry. You can see the trend emerge over time (from 1980 until present) in the video above, created at NASA’s Scientific Visualization Studio. The season just before the drought spikes up—that’s Hurricane Katrina along with six others—and then, radio silence.

A pattern like this is likely to make people wonder whether it’s being driven by a distinct change in the climate. Is there anything about this nine-year drought, or the conditions that allowed it, that will make a major Atlantic hurricane more or less likely this year? According to the study’s analysis, a string of lucky hurricane-less years this long is likely to happen only once every 177 years—pretty long odds. But it’s certainly possible that this is just a fluke, a weird statistical anomaly.

In fact, there are a number of reasons to believe that this barren stretch is merely a lucky break—and a bit of a misleading one to boot. “Those nine years haven’t been uniformly quiet,” says Timothy Hall, a hurricane researcher at the NASA Goddard Institute for Space Studies and co-author of the study. “By some measures they’ve been about average.” Since 2005, hurricane seasons have released an average amount of energy. The number of storms per year has stayed constant. And there have been plenty of major landfalls in Caribbean islands over those years, says Hall—just not in Texas or Florida.

Even more, a lack of major hurricanes doesn’t mean a lack of Category 3 storms—it merely means that at the moment of landfall, a hurricane wasn’t classified as such. Hurricane Sandy, for example, wasn’t even technically a hurricane when it hit the coast, but it strengthened all the way to a Category 3 as it traveled northward.

Though the pattern between 2005 and 2015—with seven major hurricanes in the first two years, and then none at all—is admittedly unusual, those extra details mean that the drought is likely a matter of luck. The odds for a landfall next year aren’t likely to be affected by the drought, either, explains Hall. “It seems like a Bernoulli process,” he says, “which is a fancy word for tossing a coin.”

Don’t let that uncertainty lower your guard, though—especially if you’re in the insurance business. The study’s analysis showed that every year, the chance of a major hurricane landing on the Atlantic coast is 40 percent. And just because a storm doesn’t qualify as a Category 3 doesn’t mean that it won’t cause damage: Sandy, Irene, and Ike caused over $100 billion in damage combined.

The category system currently used to label storms is called the Saffir-Simpson Hurricane Wind Scale, and just like its name suggests, it’s only reflective of the wind speed achieved by a storm. But the damage caused by a hurricane depends on more than just wind speed. In Irene, for example, it was total rainfall that took the greatest toll in upstate New York, Massachusetts, and Vermont, wiping out roads and bridges as rivers overflowed. And storm surge can cause major damage, though its effects are less predictable than wind, depending on the particular construction of natural inlets and man-made barriers along the coast.

Hall is currently working to look into the hurricane drought with a more meteorological eye—looking for any physical, climate-related processes that may have contributed to the anomaly. “My hunch is there’s no single thing,” says Hall. “It was just a lucky string of slight shifts.” What is certain, he says, is that whatever major storms do hit in the future—and they will hit—are likely to be intensified by the incontrovertible rise in sea level. “Even if the statistical pattern of hurricanes remains unchanged, sea level rise will cause bigger surges for sure,” says Hall.